The long-term objectives of this project are to elucidate the mechanism of glucose transport through biomembranes and the mode by which insulin accelerates this process in adipocytes. Immediate, specific aims are: 1) To isolate by chromatography and affinity chromatography the glucose transporters from human erythrocytes and rat adipocytes. 2) To characterize them by peptide mapping and sequence analysis. 3) To investigate the mechanism of transport and the role of transporter domains by use of affinity labels, transport reconstitution, and crosslinking. 4) To investigate the mechanism by which insulin accelerates glucose transport in fat cells by cell fractionation and reconstitution, immunology, affinity labels, and examination of possible covalent modification of the transporter. The project is related to human diabetes mellitus.